Instrumentation of a side wall of a continuous casting mold with optical waveguides

ABSTRACT

First, an auxiliary cut-out ( 11, 16 ) is formed in a side wall ( 1 ) of a continuous casting mold. That cut-out extends, in the longitudinal direction, at least over the cut-out length (L) of the useful cut-out ( 10 ) and has an auxiliary cross-section orthogonal to the longitudinal direction. Then, an additional element ( 13, 14, 17 ) is inserted into the auxiliary cut-out ( 11, 16 ), and extends, in the longitudinal direction, at least over a cut-out length (L) of a later useful cut-out ( 10 ) and bounds the useful cut-out ( 10 ) orthogonally to the longitudinal direction at least over part of the periphery of the useful cut-out. The useful cut-out ( 10 ) is formed by inserting the additional element ( 13, 14, 17 ) into the auxiliary cut-out ( 11, 16 ). The useful cut-out ( 10 ) is closed all around orthogonally to the longitudinal direction. Orthogonally to the longitudinal direction, the useful cut-out has a (correspondingly small) useful cross-section and a maximum useful extent (d 3 ). The useful cross-section is defined in such a way that an optical waveguide ( 9 ) can be reversibly inserted into the useful cut-out. The production method makes it possible that a ratio of the cut-out length (L) to the maximum useful extent (d 3 ) is 100:1 or greater.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. §§ 371 national phase conversionof PCT/EP2017/059766, filed Apr. 25, 2017, which claims priority ofAustrian Patent Application No. A50373/2016, filed Apr. 27, 2016, thecontents of which are incorporated by reference herein. The PCTInternational Application was published in the German language.

TECHNICAL BACKGROUND

The present invention is based on a method for introducing a usefulcut-out into a side wall of a continuous casting mold. The usefulcut-out extends over a cut-out length in a longitudinal direction of theuseful cut-out, is closed all around orthogonally to the longitudinaldirection and has orthogonally to the longitudinal direction a usefulcross section and a maximum useful extent, wherein the useful crosssection is determined in such a way that an optical waveguide isreversibly insertable into the useful cut-out.

The present invention is also based on a side wall of a continuouscasting mold,

-   -   wherein a useful cut-out is introduced into the side wall, which        useful cut-out extends over a cut-out length in a longitudinal        direction of the useful cut-out, is closed all around        orthogonally to the longitudinal direction and has orthogonally        to the longitudinal direction a useful cross section and a        maximum useful extent,    -   wherein the useful cross section is determined in such a way        that an optical waveguide is reversibly insertable into the        useful cut-out.

During continuous casting, liquid metal is continuously poured into amold and solidifies on side walls of the mold to form a metal strandcomprising an already solidified strand shell and a still liquid core.Synchronously with the pouring of the liquid metal into the mold, themetal strand is drawn off out of the mold. The drawing off of the metalstrand is coordinated with the pouring in such a way that a castinglevel, that is the level of the liquid in the mold, remainssubstantially constant.

At the point in time at which the metal strand leaves the mold, thestrand shell must already be sufficiently thick. Otherwise, there is therisk of a shell rupture. Decisive for a stable casting process are inparticular orderly cooling and a casting rate adapted to the mold.Furthermore, the strand shell must not stick to the mold walls. Inparticular, such sticking or catching of the shell must be detected intime, since otherwise a shell rupture occurs.

To detect such sticking, it is known to measure the temperaturedistribution in the mold by corresponding sensors. Generally, thisinvolves the sensors being arranged in a two-dimensionally distributedmanner. The corresponding arrangement of the sensors and theirevaluation are known to those skilled in the art.

Thermocouples may be disturbed by electromagnetic fields. Suchdisturbing electromagnetic fields may be caused for example byelectromagnetic stirrers (MEMS=mold electromagnetic stirrer) orelectromagnetic brakes (EBM=electromagnetic brake). Since the use ofsuch electromagnetic stirrers and electromagnetic brakes is increasing,there is an increasing problem of disturbances.

In order to reduce the electromagnetic disturbances in the case ofthermocouples, it is known to twist and shield the lines. Furthermore,filters are often additionally installed, in order to reduce disturbingfrequencies. However, both measures generally have a negative influenceon the capability of detecting catching of the shell. Furthermore, theinstallation of many measuring points with thermocouples also quicklyencounters structural design limits.

It is also known in the prior art to detect a temperature value by meansof suitable optical waveguides, in particular by means of opticalwaveguides that are based on the fiber Bragg effect. It is also alreadyknown to use such optical waveguides in the case of continuous castingmolds.

For example, reference is made to EP 2 440 883 B1. EP 2 318 162 B1 andJP 2008 043 981 A may also be mentioned in this connection.

In EP 2 440 883 B1, the optical waveguide is placed onto the side wallof the continuous casting mold. Then a coating is applied to that sideof the side wall onto which the optical waveguide has been placed. Thecoating fixes the optical waveguide. After the fixing, the opticalwaveguide is undetachably connected to the side wall.

In EP 2 318 162 B1, the optical waveguide is applied to a probe. Theprobe is inserted into a groove, a bore or a similar opening and canalso be removed from it again. In EP 2 318 162 B1, the optical waveguideis used for the purpose of detecting the height of the casting level.Only a relatively small extent of the optical waveguide in the verticaldirection is required for this purpose.

In JP 2008 043 981 A1, an optical waveguide is surrounded by a metaltube and is secured, including the metal tube, in the side wall of acontinuous casting mold.

WO 2015/058 911 A1 discloses in a first exemplary embodiment introducinga groove into a side wall of a continuous casting mold, placing a firstfoil onto the groove base, placing a cannula with an optical waveguideonto the first foil, then placing a second foil onto the first foil andthe optical waveguide and finally covering or closing the groove with afiller. WO 2015/058 911 A1 also discloses in a second exemplaryembodiment introducing into a side wall of a continuous casting mold abore of a diameter that is slightly greater than the diameter of acannula containing an optical waveguide and inserting the cannula withthe optical waveguide into the bore. WO 2015/058 911 A1 also discloses athird exemplary embodiment introducing into a side wall of a continuouscasting mold a bore of a diameter that is considerably greater than thediameter of a cannula containing an optical waveguide and inserting thecannula with the optical waveguide into the bore.

WO 2011/098 309 A1 discloses introducing into a side wall of acontinuous casting mold grooves into which optical waveguides areplaced. The grooves are then closed again. The optical waveguides arefixed by hold-down devices.

DE 10 2010 008 480 A1 discloses introducing into a side wall of acontinuous casting mold a groove into which an optical waveguide isplaced. The groove is then closed again. The optical waveguide is fixedin the groove.

WO 03/035 306 A1 discloses introducing into a side wall of a continuouscasting mold coolant channels into which displacement rods are theninserted to reduce the cross section.

JP 2008 260 046 A discloses introducing a bore into the side wall of amold. An optical waveguide provided with a protective casing is insertedinto the bore. A guiding wire may be additionally fixed on theprotective casing, and the wire can be inserted together with theoptical waveguide into the bore.

SUMMARY OF THE INVENTION

The object of the present invention is to create possibilities forallowing an optical waveguide to be reversibly inserted into the sidewall in an easy way. It is intended that the optical waveguide should inthis case be able to extend over a great length, in particular seen inthe longitudinal direction of the useful cut-out.

The object is achieved by a method disclosed herein.

According to the invention, for introducing the useful cut-out, it isprovided

-   -   that first an auxiliary cut-out is introduced into the side        wall, which auxiliary cut-out extends at least over the cut-out        length of the useful cut-out in the longitudinal direction and        has orthogonally to the longitudinal direction an auxiliary        cross section that is greater than the useful cross section,    -   that an additional element is inserted into the auxiliary        cut-out; the additional element is formed as a rod with at least        one groove arranged on its outer side or as a tube and extends        at least over the cut-out length of the useful cut-out in the        longitudinal direction,    -   that by inserting the additional element into the auxiliary        cut-out, the useful cut-out is formed and    -   that seen orthogonally to the longitudinal direction, the        surfaces of the rod that bound the groove also bound the useful        cut-out over part of its circumference and the side wall bounds        the useful cut-out over the remaining part of its circumference        or the inner side of the tube bounds the useful cut-out over its        entire circumference.

The additional element remains permanently in the side wall. It isconnected directly to the side wall. The additional element mayalternatively be arranged irreversibly, that is fixedly andnon-removably, or reversibly in the side wall. However, in both casesthe useful cut-out formed by the additional element represents aremaining cavity into which the optical waveguide can later bereversibly inserted. By this procedure it is possible to create a usefulcut-out with a small useful cross section (for example a diameter ofabout 1.5 to 3.0 mm, in particular of 1.8 to 2.5 mm), the cut-out lengthextends over the entire, or virtually the entire, height or width of theside wall.

For example, the auxiliary cut-out may be formed as a groove that isopen toward the cold side of the side wall. In this case, the additionalelement only partially fills the auxiliary cut-out toward the cold side.The part of the auxiliary cut-out remaining toward the cold side, asseen from the additional element, is in this case filled from the coldside with a filling material. The filling material preferably coincideswith the material of the side wall toward the hot side. Therefore, ifthe side wall consists for example of copper (as is regularly the casein particular when continuously casting steel), the filling material ispreferably also copper. The same applies in the case a filling ofanother material. As a result of the filling material, the additionalelement is completely surrounded on the cold side by the coatingmaterial. The cold side is that side of the side wall that is facingaway from the liquid metal during the operation of the continuouscasting mold. Conversely, the hot side is that side of the side wallthat is adjacent to the liquid metal during the operation of thecontinuous casting mold.

As an alternative to the auxiliary cut-out being formed as a groove thatis open toward the cold side of the side wall, the auxiliary cut-out maybe formed as a closed cut-out, seen orthogonally to the longitudinalextent. In particular, the cut-out may be a bore. The bore may forexample have a diameter that is as a minimum 6 mm, preferably at least 8mm, in particular at least 10 mm. As a maximum, the diameter may be upto 20 mm, preferably not exceeding a value of 15 mm, in particular of 12mm.

For a closed cut-out, it is for example possible that the additionalelement substantially fills the auxiliary cut-out.

The additional element preferably consists of the same material as theside wall. As a result, on the one hand, a uniform coefficient ofthermal conduction is obtained, and on the other hand, a uniformcoefficient of expansion of the side wall and the additional element isobtained.

The maximum useful extent is equal to the diameter of a circlecircumscribing the useful cross section, that is to say the circle withthe smallest diameter that, on the one hand, completely surrounds theuseful cross section, and on the other hand, touches the useful crosssection, but does not intersect it. In an analogous way, a minimumuseful extent is equal to the diameter of a circle inscribed in theuseful cross section, that is the circle with the greatest diameter thatis completely surrounded by the useful cross section and touches theuseful cross section but does not intersect it. The maximum usefulextent has for example a value of typically 1.5 mm to 4 mm. The minimumuseful extent typically has a value of 1.5 mm to 3 mm. Depending on thetype of useful cross section, the minimum useful extent typically liesin the range between 57% and 100% of the maximum useful extent. In acircular useful cross section, the ratio is, for example, 100%. In asquare useful cross section, the ratio is, for example, about 71%. Bycontrast, the cut-out length is considerably greater than the maximumuseful extent. It may, for example, be 500 to 800 mm. In particular, itis possible that a ratio of the cut-out length to the maximum usefulextent is at least 100:1. Still greater ratios are also possible, forexample at least 120:1, at least 150:1, at least 200:1, at least 300:1,at least 400:1 and of at least 500:1. The reason why such a great ratiois achievable is that, because of the manner in which the useful cut-outis produced, the achievable cut-out length is not limited at all in thecase of an auxiliary cut-out formed as an open groove, is limited by thetransverse extent of the auxiliary cut-out, but not by the transverseextent of the useful cut-out in the case of an auxiliary cut-out formedas a closed cut-out.

The object is also achieved by a side wall with the features disclosedherein.

According to the invention, a side wall of the type mentioned at thebeginning is developed

-   -   in that an additional element is arranged in the side wall,        which additional element is formed as a rod with at least one        groove arranged on its outer side or is formed as a tube and        extends at least over the cut-out length of the useful cut-out        in the longitudinal direction,    -   in that, seen orthogonally to the longitudinal direction, the        surfaces of the rod that bound the groove bound the useful        cut-out over part of its circumference and the side wall bounds        the useful cut-out over the remaining part of its circumference        or the inner side of the tube bounds the useful cut-out over its        entire circumference and    -   in that the additional element is completely surrounded by        material toward the cold side of the side wall.

The additional element remains permanently in the side wall. It isconnected directly to the side wall. The additional element mayalternatively be arranged irreversibly, that is fixedly andnon-removably, or reversibly in the side wall. However, in both casesthe useful cut-out formed by the additional element represents aremaining cavity into which the optical waveguide can later bereversibly inserted. As a result, the useful cut-out may, as alreadymentioned, in particular have a small useful cross section, which mayfor example correspond to a diameter of about 1.5 mm to 3.0 mm, inparticular of 1.8 mm to 2.5 mm, while the cut-out length may extend overthe entire height or width of the side wall.

The advantageous developments of the side wall correspond substantiallyto those of the method.

For instance, it is possible in particular that the additional elementis coated with a coating material toward the cold side, the fillingmaterial preferably coinciding with the material of the side wall towardthe hot side.

It is also possible that the side wall has an auxiliary cut-out, whichextends at least over the cut-out length of the useful cut-out in thelongitudinal direction, is formed as a closed cut-out, seen orthogonallyto the longitudinal extent, and has orthogonally to the longitudinaldirection an auxiliary cross section that is greater than the usefulcross section, and that the additional element is inserted into theauxiliary cut-out. The auxiliary cut-out may in this case be formed inparticular as a bore.

The additional element may substantially fill the auxiliary cut-out.

The additional element preferably consists of the same material as theside wall.

As before, it is possible that the useful cut-out has a maximum usefulextent, seen orthogonally to the longitudinal direction, and a ratio ofthe cut-out length to the maximum useful extent is at least 100:1. Here,too, greater ratios are possible, for example at least 120:1, at least150:1, at least 200:1, at least 300:1, of at least 400:1 and of at least500:1.

The properties, features and advantages of this invention describedabove and the manner in which they are achieved will be more clearly anddistinctly comprehensible in conjunction with the following descriptionof the exemplary embodiments, which are explained in greater detail inconjunction with the schematically represented drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows part of a continuous casting mold from the side,

FIG. 2 shows a continuous casting mold from above,

FIG. 3 shows an enlarged representation of a detail from FIG. 1,

FIG. 4 shows a side wall with a groove,

FIG. 5 shows the side wall from FIG. 4 with a tube placed into thegroove,

FIG. 6 shows the side wall from FIG. 4 with a covering placed into thegroove,

FIG. 7 shows a tube,

FIG. 8 shows the side wall from FIG. 5 in the finished state,

FIG. 9 shows the side wall from FIG. 6 in the finished state,

FIG. 10 shows a side wall with a bore and

FIG. 11 shows the side wall from FIG. 10 in the finished state.

DESCRIPTION OF EMBODIMENTS

Side walls 1 of a continuous casting mold are used, in a waycorresponding to the representation in FIGS. 1 and 2, to bound a liquidmetal 2, for example steel or aluminum, while the metal 2 is solidifyingon hot sides 3 of the side walls 1 to form a strand shell 4 with a stillliquid core 5. The metal strand 6, consisting of the strand shell 4 andthe liquid core 5, is drawn off out of the continuous casting mold in adrawing-off direction x. The continuous casting mold may in a waycorresponding to the representation in FIGS. 1 and 2, have a number ofplates, which together form a rectangular cavity for receiving theliquid metal 2. Alternatively, the continuous casting mold may be formedas an individual, closed side wall 1 completely surrounding the cavity.In many cases, adjusting devices 8, which can set the size of thecavity, are arranged on cold sides 7.

Further elements of the continuous casting mold are in particularcooling devices, by means of which the side walls 1 are cooled. Thecooling devices are not shown in the figures for reasons of overallclarity.

A height H of the side walls 1 often lies in the range of 50 cm to 2 m.A width B may lie in the range between 20 cm and 3 m. A thickness Dusually lies in the range of a few cm, for example 20 mm to 60 mm.

For the thermal monitoring of the continuous casting mold, opticalwaveguides 9 are arranged in the side walls 1, as seen in the detail ofFIG. 3. The corresponding use of optical waveguides 9 is generally knownto those skilled in the art. It is based on the fiber Bragg effect. Theoptical waveguides 9 may alternatively run horizontally or vertically inthe side walls 1. In FIGS. 1 and 2, a horizontally running opticalwaveguide 9 and a vertically running optical waveguide 9 arerespectively shown. There are generally a number of optical waveguides9, which may for example all run vertically or all run horizontally.However, mixed vertical and horizontal direction or oblique directionforms are also possible. Thus, for reasons of easier assembly andgreater operational reliability, it is for example of advantage toinsert the optical waveguides 9 horizontally into the side wall 1. Mostof the optical waveguides 9 in this case run only horizontally withinthe side wall 1.

In order, for example, to be able to detect the height of a castinglevel exactly, there may be a single further optical waveguide 9,referred to hereinafter as the additional optical waveguide 9. Seen inthe direction of the height, the additional optical waveguide 9 mustovercome a certain difference in height. This may be achieved on the onehand by the additional optical waveguide 9 running vertically. In thiscase, the additional optical waveguide 9 is inserted into the side wall1 from above or from below. Preferably, however, the additional opticalwaveguide 9 is also inserted laterally into the side wall 1, but runswithin the side wall 1 at an angle to the horizontal. The angle isdifferent from 90°. It may for example lie between 10° and 45°. Theadditional optical waveguide 9 in this case extends over a length suchthat, with allowance for the angle that it forms with the horizontal, itovercomes the desired difference in height. The difference in heightmay, for example, be between 80 mm and 150 mm, in particular between 90mm and 120 mm, for example about 100 mm.

Customary suitable optical waveguides 9 often have a diameter d1 (FIG.3), which lies in the range well below 1 mm, for example about 150 μm to250 μm. The optical waveguides 9 may be surrounded by a protectivecasing 9′. The protective casing 9′ is often also referred to as acannula. The protective casing 9′ often consists of metal, for examplehigh-grade steel. Including the protective casing 9′, the opticalwaveguides 9 often have a diameter d2, which lies in the range ofsomewhat over 1 mm, for example 1.2 mm to 2.0 mm.

For receiving the optical waveguides 9, useful cut-outs 10 have beenintroduced into the side wall 1. The useful cut-outs 10 extend over arespective cut-out length L in a longitudinal direction of therespective useful cut-out 10. The cut-out length L may coincide with theheight H or the width B of the respective side wall 1. In this case, itis a continuous, useful cut-out 10, which is open to both sides.Alternatively, the cut-out length L may be shorter. In this case, theuseful cut-out 10 ends in the side wall 1 in a way similar to a blindbore. Orthogonally to the longitudinal direction, the useful cut-outs 10are closed all around. They have orthogonally to the longitudinaldirection a cross section and a maximum extent. The cross section andthe maximum transverse extent of the useful cut-outs 10 are referred tohereinafter as the useful cross section and the maximum useful extent.This choice of words only serves for verbal differentiation from othercross sections and extents.

Because the useful cut-outs 10 are intended for receiving the opticalwaveguides 9, the useful cross section is determined in such a way thatone optical waveguide 9 can be respectively inserted into the usefulcut-out 10. The optical waveguides 9 may alternatively be inserted intouseful cut-outs 10 with the protective casings 9′ or without theprotective casings 9′. The minimum useful extent must be slightlygreater than the diameter of the optical waveguides 9 with or withoutthe protective casings 9′. Accordingly, the minimum useful extent shouldbe above 1.2 mm to 2.0 mm, for example 1.5 mm to 3.0 mm, depending onthe optical waveguide that is used. Depending on the form of the usefulcross section, the maximum useful extent either has the same value or isslightly greater. In particular, it may lie between 1.5 mm and 4.0 mm.The maximum useful extent should only assume values above 3 mm when thisis required to achieve a sufficiently great minimum useful extent.

The possibility of inserting the optical waveguides 9 into the usefulcut-outs 10 is reversible. The optical waveguides 9 can therefore alsobe removed again from the useful cut-outs 10. Therefore, for a circularuseful cross section, the useful cut-outs 10 may, for example, have adiameter d3, which lies in the range between 1.5 mm and 3.0 mm, inparticular between 2.0 mm and 2.5 mm. For a circular useful crosssection, the diameter d3 corresponds both to the minimum useful extentand to the maximum useful extent. In the case of a square useful crosssection, the indicated numerical values may apply for example to theside length of the square shape useful cross section. In the case of asquare useful cross section, the maximum useful extent is determined bythe diagonal of the square. For the maximum useful cross section, thenumerical values are therefore to be provided with a factor of somewhatover 1.4. It is assumed hereinafter that the useful cross section iscircular. However, similar circumstances also apply in the case of someother useful cross section.

As already mentioned, the height H of the side walls 1 often lies in therange from 50 cm to 2 m, and the width B lies in the range between 20 cmand 3 m. As likewise already mentioned, it is possible that the cut-outlength L coincides with the height H or the width B of the respectiveside wall 1. A ratio of the cut-out length L to the maximum usefulextent for example the quotient L/d3) can therefore become very large.Although it is possible that the ratio only assumes relatively smallvalues, for example 50 or 80. It is however similarly possible thatgreater values are assumed, for example 100:1 or more, 120:1 or more,150:1 or more, and so on. How this can be achieved is explained in moredetail below in conjunction with the further FIGS. 4-6.

For producing at least one useful cut-out 10, first an auxiliary cut-out11 is introduced into the side wall 1. For example, corresponding to therepresentation in FIG. 4, a groove 11 may be introduced into the sidewall 1 as the auxiliary cut-out 11. The introduction of the groove 11takes place in this case from the cold side 7 of the side wall 1. Thegroove 11 is therefore open toward the cold side 7 of the side wall. Thegroove 11 may for example be formed in a semicircular or V-shaped mannerin cross-section. Other forms are also possible. The groove 11 may forexample be introduced into the side wall by simple milling or the like.A groove depth t is dimensioned such that the groove base 12 (i.e. thedeepest point of the groove 11) is at a predetermined distance a fromthe hot side 3 of the side wall 1. The auxiliary cut-out 11 extends atleast over the cut-out length L of the useful cut-out 10 in thelongitudinal direction of the (later) useful cut-out 10. Orthogonally tothe longitudinal direction, the auxiliary cut-out 11 has a crosssection. The cross section of the auxiliary cut-out 11 is greater thanthe useful cross section. It is referred to hereinafter as the auxiliarycross section. This choice of words only serves however for verbaldifferentiation from other cross sections.

Then, in a way corresponding to the representation in FIGS. 5 and 6, anadditional element 13 or 14 is inserted into the auxiliary cut-out 11.The additional element 13, 14 preferably consists of the same materialas the side wall 1. If, therefore, the side wall 1 consists of copper,for example, the additional element 13, 14 also consists of copper.Alternatively, the additional element 13, 14 may consist of a materialthat has similar properties to the material of the side wall 1. Thisapplies in particular to the coefficient of thermal expansion andpreferably also to the thermal conductivity.

The additional element 13 or 14 likewise extends at least over thecut-out length L of the useful cut-out 10 in the longitudinal direction.For example, in a way corresponding to the representation in FIG. 5, theadditional element 13 may be formed as a tube 13, the inward side ofwhich bounds the useful cut-out 10. Seen orthogonally to thelongitudinal direction, in this case the useful cut-out 10 is completelysurrounded or bounded by the additional element 13.

Alternatively, the additional element 14 may be formed in a waycorresponding to the representation in FIG. 6 as a covering 14. In thiscase, the covering 14 covers the groove base 12. The region between thecovering 14 and the groove base 12 corresponds in this case to theuseful cut-out 10. Consequently, seen from the useful cut-out 10, thecovering 14 is arranged on the cold side 7 of the side wall 1. Seenorthogonally to the longitudinal direction, it partially, but notcompletely, bounds the useful cut-out 10. In both cases, consequently,the useful cut-out 10 is formed by the insertion of the additionalelement 13, 14 into the auxiliary cut-out 11.

The additional element 13 which is developed as a tube 13 may, in a waycorresponding to the representation in FIG. 7, consist of a number ofportions 13′, which are placed one after the other, seen in thelongitudinal direction of the useful cut-out 10. The portions 13′ may inthis case have guiding surfaces 13″ that interact with one another, sothat the useful cut-out 10 passes through continuously. Also forexample, corresponding to the representation in FIG. 7, the usefulcut-out 10 may be slightly widened in the end regions of the portions13′, in order to facilitate the leading in and leading through of theoptical waveguide 9 through all of the portions 13′.

The additional element 13 or 14 only partially fills the auxiliarycut-out 11 or groove 11 toward the cold side 7 of the side wall 1.Depending on the form of the groove 11 and depending on the developmentof the additional element 13 or 14, the degree of filling may be atgreater or smaller values. For example, the degree of filling may liebetween 30% and 10%. Sometimes, the degree of filling is even less. InFIGS. 8 and 9, after the insertion of the additional element 13 or 14,the part of the auxiliary cut-out 11 remaining toward the cold side 7 ofthe side wall 1 is filled from the cold side 7 of the side wall 1 with afilling material 15. This completely surrounds the additional element 13or 14 by the filling material 15 on the cold side 7 of the side wall 1.In particular, the filling material 15 is cohesively connected to theside wall 1 and the additional element 13 or 14. As a result, theadditional element 13, 14 is arranged irreversibly, that is fixedly,permanently and non-removably, in the side wall 1 or in the auxiliarycut-out 11. As a result, the additional element 13 or 14 is connecteddirectly to the side wall 1 without an intermediate space. Theadditional element 13 or 14 defines a cavity, that is a space, that isnot filled with material, into which the optical waveguide 9 can laterbe reversibly inserted and which cavity is the useful cut-out 10.

In the ideal case, the filling material 15 coincides with the materialof the side wall 1 toward the hot side 3. If the side wall 1 consists,for example, of copper, the filling material is also ideally consists ofcopper. This also applies whenever the side wall 1 has on the hot side 3an additional coating 3′, for example of nickel, chromium or ceramic.Also in this case, the material of the side wall 1 means the “actual”material of the side wall 1, not the material of the coating 3′. FIGS. 8and 9 show the corresponding side walls. The filling material 15 is inthis case preferably applied by coating to the cold side 7 of the sidewall 1. Alternatively, some other material may be used as fillingmaterial 15. This applies in particular whenever the groove 11 isrelatively narrow. In such cases, nickel, chromium, brass or a syntheticresin may be used for example as the filling material 15. Depending onthe situation of the individual case, application by coating may also bepossible in this case.

Any coating applied on the cold side 7 may for example be applied to athermal spraying process or to a galvanic process. Correspondingprocesses are generally known to those skilled in the art. For example,as thermal processes there are wire-flame spraying, plasma spraying,powder-vapor spraying, high-velocity flame spraying and cold-gasspraying. What is important for an applied 7 coating is that the fillingmaterial 15 be applied as one. If the filling material 15 coincides withthe material of the side wall 1 toward the hot side 3, a uniform sidewall 1 is formed during the coating, in which a transition from theoriginal side wall 1 to the filling material 15 is not detectable, or isscarcely detectable. Also, the resultant thermal conductivity of theside wall 1, except for the useful cut-out 10, is unchanged with respectto the thermal conductivity of the side wall 1, as it was before theintroduction of the groove 11.

As mentioned above, the groove 11 may be for example be V-shaped orsemicircular. Irrespective of the specific form of the groove 11 andcorresponding to the representations in FIGS. 5 and 6, a further groove12′ has been introduced into the groove base 12 itself. In thedevelopment according to FIG. 5, the additional element 13 is formed asa tube 13, and the further groove 12′ may in particular be formed tomatch the outside diameter of the tube 13. In the development accordingto FIG. 6, the additional element 14 is formed as a covering 14, and thefurther groove 12′ is preferably determined by the size of the lateruseful cut-out 10. In particular, in this case, corresponding to therepresentation in FIG. 5, the covering 14 may be formed as a simplesheet-like covering, which covers the further groove 12′.

A further possibility for introducing the useful cut-out 10 into theside wall 1 is explained below in conjunction with FIGS. 10 and 11.According to FIGS. 10 and 11, an auxiliary cut-out 16 is introduced intothe side wall 1. In FIG. 10, as also in FIGS. 4 to 9, the auxiliarycut-out 16 extends at least over the cut-out length L of the usefulcut-out 10 in the longitudinal direction. Also, as in FIGS. 4 to 9, theauxiliary cut-out 16 has, orthogonally to the longitudinal direction, anauxiliary cross section that is greater than the useful cross section.However, in contrast to the development of FIGS. 4 to 9, the auxiliarycut-out 16 of FIGS. 10 and 11 is formed as a closed cut-out, seenorthogonally to the longitudinal extent. For example, the auxiliarycut-out 16 may be a bore with a correspondingly large diameter d4. Thediameter d4 may for example lie between 6 mm and 20 mm, and inparticular between 8 mm and 15 mm.

Then, an additional element 17 is inserted into the auxiliary cut-out16. FIG. 11 shows the corresponding state. The additional element 17preferably consists of the same material as the side wall 1. Thestatements made above in relation to the additional elements 13, 14 maybe applied in an analogous way.

The additional element 17 extends at least over the cut-out length L ofthe useful cut-out 10 in the longitudinal direction. It is preferablyformed, corresponding to the representation in FIG. 11, as a rod 17,which substantially fills the auxiliary cut-out 16, but has on its outerside at least one groove 18 extending in the longitudinal direction ofthe useful cut-out 10. Seen orthogonally to the longitudinal direction,the additional element 17 (or the surfaces of the additional element 17that bound the groove 18) only bound(s) the useful cut-out 10 over partof its circumference. Over the remaining part of its circumference, theuseful cut-out 10 is in this case bounded by the side wall 1.Alternatively, analogous to the development of the tube 13, here, too,the additional element 17 could be formed as a tube in particular, as amultipiece tube. Also in the case of the development of FIGS. 10 and 11,however, the useful cut-out 10 is formed by the insertion of theadditional element 17 into the auxiliary cut-out 16.

When the auxiliary cut-out 16 is closed all around, in particular as abore, the practically achievable length is limited by the diameter d4.In practice, generally, the depth of an achievable bore can at most beabout 100 times the diameter of the bore. This is also applied in thecontext of the present invention. With a diameter d4 of, for example, 10mm, a maximum bore depth of about 1000 mm is therefore achievable, witha diameter d4 of, for example 12 mm, a maximum bore depth of about 1200mm is achievable. With a smaller or greater diameter d4, the achievablebore depth is correspondingly smaller or greater. The achievable boredepth, and consequently the cut-out length L, is limited by the diameterd4 of the auxiliary cut-out 16, but not by the diameter d3 or adimension equivalent thereto of the useful cut-out 10. It is thereforepossible to achieve a great cut-out length L of the useful cut-out 10,although the maximum useful extent of the useful cut-out 10 is small.

In the minimum case, it is adequate if the additional element has asingle groove 18. Alternatively, the additional element 17 may have aplurality of such grooves 18. Various advantageous effects can berealized depending on the number and arrangement of the grooves 18 alongthe circumference of the additional element 17 and depending on theorientation of the additional element 17 in the auxiliary cut-out 16.For example, corresponding to FIG. 11, there may be two grooves 18offset by 180° with respect to one another along the circumference. Ifthe additional element 17 is oriented in the auxiliary cut-out 16 suchthat the two grooves 18 define a plane that runs parallel to the hotside 3 of the side wall 1, a redundancy and/or a spatial resolution canbe achieved in the temperature detection. If, on the other hand, theadditional element 17 is oriented in the auxiliary cut-out 18 such thatthe two grooves 18 define a plane that is oriented orthogonally to thehot side 3 of the side wall 1, the temperature gradient can bedetermined. With, for example, three or four grooves 18, which aredistributed uniformly over the circumference of the additional element17, both effects can be realized.

In the side wall 1 according to FIGS. 10 and 11, a distance of theadditional element 17 from the side wall 1 should be as small aspossible (apart from in the region of the groove 18 or the grooves 18),in order to have as little influence as possible on the heat removalfrom the hot side 3 to the cold side 7 of the side wall 1. This can beachieved by appropriate matching of the diameter of the additionalelement 17 to the diameter d4 of the auxiliary cut-out 16. For example,a snug fit of the additional element 17 in the auxiliary cut-out 16 maybe realized. In this case, after having been inserted into the auxiliarycut-out 16, the additional element 17 can also be removed again from theauxiliary cut-out 16. In this case, although the additional element 17is not connected cohesively to the side wall 1, it is still connecteddirectly. On account of the additional element 17, there still remains acavity, that is a space not filled with material, into which the opticalwaveguide 9 can later be reversibly inserted, that is when theadditional element 17 is arranged in the auxiliary cut-out 16, and whichcavity is the useful cut-out 10.

Alternatively, a snug fit of the additional element 17 in the auxiliarycut-out 16 may be achieved for example by the diameter of the additionalelement 17 being minimally greater than the diameter d4 of the auxiliarycut-out 16, as long as the additional element 17 and the side wall 1 areat the same temperature. In this case, for example, the additionalelement 17 may be cooled below the temperature of the side wall 1, sothat the additional element 17 has thermally shrunk slightly. Inaddition or as an alternative, the side wall 1 may be heated. In thisstate, the additional element 17 can then be readily inserted into theauxiliary cut-out 16. The subsequent thermal expansion of the additionalelement 17 and/or contraction of the side wall 1 has the effect that theadditional element 17 comes to bear against the side wall 1 tightly andunder pressure. It therefore cannot any longer be removed from theauxiliary cut-out 16. The heat transfer from the side wall 1 into theadditional element 17 and vice versa is therefore very good. Inparticular, the good heat transfer from the side wall 1 into theadditional element 17 prevents the side wall 1 from being able to beheated independently of the additional element 17, or the additionalelement 17 from being able to be cooled down independently of the sidewall 1. Otherwise, the above statements made in relation to the case ofa snug fit apply.

The additional element 17 should preferably be secured in the auxiliarycut-out 16 against twisting. In the case of a snug fit, twist preventionis obtained automatically by the pressure under which the additionalelement 17 lies against the side wall 1. In the case of a snug fit,corresponding securing elements may be present, for example smallwedges, are known to a person skilled in the art.

The present invention has many advantages. In particular, it is possibleto produce a side wall 1 of a continuous casting mold into which usefulcut-outs 10 with a very small maximum useful extent (for examplediameter d3), seen transversely to the longitudinal direction of theuseful cut-outs 10, can be introduced over the entire height H or widthB or generally over a great cut-out length L in the longitudinaldirection of the useful cut-outs 10. This enables optical waveguides 9with or without a protective casing 9′ to be reversibly inserted intothe useful cut-outs 10. In particular, in the case of damage to anoptical waveguide 9, the damaged optical waveguide 9 can consequently bereadily exchanged. This exchangeability is of importance in particularbecause the failure of an individual optical waveguide leads to thefailure of many individual temperature measuring points. It is alsopossible first to introduce only the useful cut-outs 10 into the sidewall 1 and only subsequently, after the forming of the useful cut-outs10, to insert the optical waveguides, 9 with or without a protectivecasing 9′ into the useful cut-outs 10.

Although the invention has been illustrated more specifically anddescribed in detail by the preferred exemplary embodiment, the inventionis not restricted by the examples disclosed and other variations may bederived therefrom by a person skilled in the art without departing fromthe scope of protection of the invention.

LIST OF DESIGNATIONS

-   1 Side walls-   2 Liquid metal-   3 Hot sides-   3′ Coating-   4 Strand shell-   5 Liquid core-   6 Metal strand-   7 Cold sides-   8 Adjusting devices-   9 Optical waveguide-   9′ Protective casing-   10 Useful cut-outs-   11 Auxiliary cut-out (groove)-   12 Groove base-   12′ Further groove-   13 Additional element (tube)-   13′ Portions-   13″ Guiding surfaces-   14 Additional element (covering)-   15 Filling material-   16 Auxiliary cut-out (bore)-   17 Additional element (rod)-   18 Grooves of the rod-   a Distance-   B Width-   d1 to d4 Diameter-   D Thickness-   H Height-   L Cut-out length-   t Groove depth-   x Drawing-off direction

1. A method for introducing a useful cut-out into a side wall of acontinuous casting mold, wherein the useful cut-out extends over acut-out length in a longitudinal direction of the useful cut-out, isclosed all around orthogonally to the longitudinal direction and hasorthogonally to the longitudinal direction a useful cross section and amaximum useful extent, wherein the useful cross section is determined sothat an optical waveguide is reversibly insertable into and removablefrom the useful cut-out; first introducing an auxiliary cut-out into theside wall, wherein the auxiliary cut-out extends at least over thecut-out length of the useful cut-out in the longitudinal direction andthe auxiliary cut-out has orthogonally to the longitudinal direction anauxiliary cross section that is greater than the useful cross section;inserting an additional element into the auxiliary cut-out, theadditional element is formed as a rod with at least one groove arrangedon its outer side or is formed as a tube and the rod or the tube extendsat least over the cut-out length of the useful cut-out in thelongitudinal direction, wherein inserting the additional element intothe auxiliary cut-out, forms the useful cut-out; and wherein, seenorthogonally to the longitudinal direction, the surfaces of the rod thatbound the groove also bound the useful cut-out over part of itscircumference and the side wall bounds the useful cut-out over theremaining part of its circumference or the inner side of the tube boundsthe useful cut-out over its entire circumference.
 2. The method asclaimed in claim 1, wherein the sidewall has a cold side and a warmside; the method comprising: forming the auxiliary cut-out as a groovethat is open toward the cold side of the side wall, only partiallyfilling the auxiliary cut-out toward the cold side with the additionalelement so that part of the auxiliary cut-out remains toward the coldside, and as seen from the additional element, filling the auxiliarycut-out from the cold side with a filling material.
 3. The method asclaimed in claim 1, further comprising: forming the auxiliary cut-out asa closed cut-out, seen orthogonally to the longitudinal extent.
 4. Themethod as claimed in claim 3, further comprising the additional elementsubstantially filling the auxiliary cut-out with the additional element.5. The method as claimed in claim 1, wherein the additional elementconsists of the same material as the side wall.
 6. The method as claimedin claim 1, wherein a ratio of the cut-out length to a maximum usefulextent of a useful cut-out is at least 100:1.
 7. A side wall of acontinuous casting mold, comprising: a useful cut-out in the side wall,the useful cut-out extending over a cut-out length in a longitudinaldirection of the useful cut-out, the useful cut-out is closed all aroundorthogonally to the longitudinal direction and has a useful crosssection and a maximum useful extent; wherein the useful cross section isdetermined such that an optical waveguide is reversibly insertable intothe useful cut-out; an additional element is arranged in the side wall,the additional element being formed as a rod with at least one groovearranged on an outer side of the additional element or as a tube thatextends at least over the cut-out length of the useful cut-out in thelongitudinal direction; seen orthogonally to the longitudinal direction,surfaces of the rod that bound the groove also bound the useful cut-outover part of a circumference thereof, and the side wall bounds theuseful cut-out over the remaining part of the circumference thereof orthe inner side of the tube bounds the useful cut-out over the entirecircumference thereof; and wherein the additional element is completelysurrounded by material toward the cold side of the side wall.
 8. Theside wall as claimed in claim 7, further comprising the additionalelement is coated toward the cold side with a coating material.
 9. Theside wall as claimed in claim 7, further comprising: the side wall hasan auxiliary cut-out extending at least over the cut-out length of theuseful cut-out in the longitudinal direction, the auxiliary cut-out isformed as a closed cut-out, seen orthogonally to the longitudinalextent, and has orthogonally to the longitudinal direction an auxiliarycross section that is greater than the useful cross section, and in thatthe additional element is inserted into the auxiliary cut-out.
 10. Theside wall as claimed in claim 9, wherein the auxiliary cut-out is formedas a bore.
 11. The side wall as claimed in claim 9, wherein theadditional element substantially fills the auxiliary cut-out.
 12. Theside wall as claimed in claim 7, wherein the additional element consistsof the same material as the side wall.
 13. The side wall as claimed inclaim 7, wherein a ratio of the cut-out length to the maximum usefulextent is at least 100:1. 14.-18. (canceled)